Generally, in prior art automatic weapon systems, the cartridge or round is introduced into the receiver and ramped angularly into the stationary firing chamber. Angular ramping has been heretofore required, in most cases, because of the configuration of the cartridge and its position in the linked belt on the feed tray. As a result, the ammunition feed and ejection mechanism designs were slaved to the design of the feed tray, firing chamber, reciprocating bolt and cartridge.
Recently, consideration has been given to the concept of a reciprocating firing chamber for automatic weapons which would telescope over the round for firing thereof. Such concept, while permitting lateral or transverse feed to, and ejection from, a receiver opening in the path of movement of the firing chamber, presented problems with respect to synchronization of the movement of the firing chamber between the in and out of battery positions with the feed and ejection functions as well as problems of axial centering of the round in the receiver for pickup by the reciprocable firing chamber in moving to the in battery position. To this end, various mechanical spring biased round centering mechanisms have been proposed as well as spring actuated feed and ejection devices. However, the effects of vibrations and recoil forces adversely affect operation of the spring biased devices, causing failures to feed and weapon stoppages.